Attrition-mill.



Patented July 13, i915.

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ATTRITION MILL.

APPLICATION min APR. 1. |911.

Patented July 13, 1915.

5 sains-SHEET 2.

25 417 59 5 F116 57 F104 f J. S. SORENSEN.

ATTRITION MILL.

APPLICATION FILED APR. I. I9II.

LHMSI Patented July I3, 1915.

5 SHEETS-SHEET 4.

I. S. SORENSIN.

Ammon MILL.

APPLICATION FILED APR. I9II. 1%U Patented July 13, 1915.

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JOHN S. SORENSEN, OF MUNCY, PENNSYLVANIA, ASSIGNOR TO SPROUT, WRON @c COMPANY, 0F MUNCY, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA.

ATTENTION-MILL.

Minoes.

Specieation of Letters Patent.

Patented dimly f3, iigf.

T0 all whom it may concern:

Be it known that I, JOHN S. SoaisNsnN, a citizen of the United States, residing at Muncy, in the county of lLycoming and State of Pennsylvania, have invented certain new and useful Improvements in Attrition-Mills, of which the following is a. specification.

This invention relates to attrition mills, and has for its object the provision of a mill in which the working parts will be reduced to a minimum and which will becapable of running at a high speed for a long continued period without any adjustment of the parts or excessive wear thereon.

Further objects of the invention are to provide a mill of such a construction that the necessity for tramming,.by which much time is lost with the mills now in common use. is entirely obviated; to provide a mill in which the bearings and moving parts will he thoroughly protected against the en traiice thereto of flying dust or particles of dirt. so that choking ofthe mill or burning of the product due to excessive friction will he overcome; to provide means whereby the mill will quickly respond to the entrance of foreign matters between the grinding plates, so as to yield to such foreign substances and thereby prevent injury to the plates, and to provide means whereby the movement of the releasing cam will be limited and the4 effectiveness of the quick release vdevice thereby increased.

All these stated objects, and such other incidental objects as will hereinafter-'appear, are attained in such a mill as is illustrated i'n the accompanying drawings, which are to be taken as a pai't of this specification. J v

i rFhe invention resides in certain novel features of construction, arrangement and combination of parts which will be hereinafter first fullv 'described and then pointed out more in detail in the appended claims.

lin the accompanyingr drawings: Figure 1 is a central vertical longitudinal section of an attrition mill embodying my present iniproveinents. Fig. 2 is an elevation of the tail end of the machine. Fig. 3 is an enlarged vertical section of the head end bear ing. Fig. 4 is a similar view of one of the inner bearings. Fig. is a detail elevation of the end bearing shown in Fig. 3. Fig. (3 is a perspective view of the base. Fig. 7 is a Anature of the product.

similar view on the line 10--10 of Fig. 8.

Fig. 11 is a similar view on the line 11.-11 of Fig. 8. Fig. 12 is a detail section on the line 12--12 of Fig. 11. Fig. 13 is a view showing the relief box in section on the line 13-13 of Fig. 11, and the cam box in elevation. Fig. 14 is a view similar to Fig. 13, but showing the parts in a. different position. Fig. v15 is a detail perspective view of the releasing cam. Fig. 16 is an enlar ed detail section of the packing ring or stu ng box fitted around the tail nd runner against the casing.

lin cari'ying out my present invention, I

employ a base 1 which may be of any desired size and is preferably a parallelograrn provided along its sockets or brackets 2, through which bolts are inserted to secure the base to a suitable foundation or fixed support. rFhe base is provided at its center with a spout 3 through which the ground material or fiour escapes to be stored or subsequently treated, as may be necessary or desirable` according to the Between each end and the spout 3, the base'is provided through its top with openings -L to reduce the weight without affecting the strength of the base, and between the spout and the said openings as well as between the said openings and the ends of the base, reinforcing ribs 5 are formed on its under side so as to reinforce the top plate of the base and also lend additional support to the devices secured upon the same. Upon its upper side, the base is formed with longitudinal ribs or abutments (3, the inner faces or Shoulders of whichJnay rise from the base .in true vertical planes, as shown at 7, and the several ribs adjacent one side of the base are arranged in exact longitudinal alinement. rFhe series of ribs or abutments are duplicated at each side of the base and each rib preferably rises from a boss 8 on the top of the base, which boss has a perfectly smooth upper face arranged in a true horizontal plane. 'Fliesel bosses form supports or seats for the pedestals presently described, and through the said bosses and the base are vertically disposed openings 9 which are internally threaded to be engaged l longitudinal side edges with by tap bolts inserted through the lower ends of the pedestals to secure the same in position. The pedestals, of `which mention has just been made, are clearly shown in Figs. l and 2 and consist of approximately triangular blocks or standards having their lower ycorners -10 planed so as to present square or right angular surfaces which are adapted to fit snugly upon the upper faces of the bosses 8 and against the inner faces of the ribs or.

abutments 6, asclearly shown in Fig. 2. A number of these pedestals are provided, two being shown to support each runner shaft, and the several pedestals are identical in construction, except that the tail end pedestal is somewhat wider than the others in order to support the end thrust bearing. Upon the sides of the pedestals, at the lower ends thereof, are preferably formed upstanding bosses 11 through which the tap.

screws 12 are inserted to engage the openings 9 in the base and thereby firmly secure the pedestals in position. In the illustrated embodiment of my invention the outer face ,or side of the lower corner of the pedestal is disposed at a true right angle to the under face of the samefand in a true vertical plane, in order that the several pedestals may be iitted upon the bosses of the base and between the ribs thereon with such nicety and accuracy that subsequent adjustment of the same will be rendered entirelyunnecessaryl The fastening screws 12 may therefore be turned home, so as to rigidly secure the pedestals in position without the use of any lock-nuts and, when the pedestals are once secured in place, they will remain fixed during the life of the machine. The bosses upon the base will provide seats raised slightly above the plane of the top of the base, while the under sides or lower ends of the pedestals are recessed between their extremities, as shown at 13, so that'the contacting surfaces will be reduced to the smallest possible area and possible wear due to any unforeseen vibration of the machine will be obviated. The upper ends of the pedestals are concave so as to present seats 14 to receive the bearings, and these seats, as well as the sides of the pedestals, project laterally beyond the central webs 15, so that openings for the securing bolts may be readily formed through the seats. The bearing shell or housing 16 is substantially a sleeve. the length of which corresponds to the width of the seat 14 and the under side of which is convex so as toit snugly upon the said seat` as shown most clearly in Figs. 9 and 10. In theunder side of the said shell, I provide threaded sockets. indicated of the pedestals and the shells, l secure the shells in place so that movement of the saine upon the pedestal will be positively prewented, and, consequently, the necessity for adjustment of the bearings will be overcome. Inasmuch as the bearing shells and the pedestals cannot move relatively to the base` wear upon these parts is positively prevented, and, when the said elements have once been assembled, they will remain fixed in place for alll time. As shown in Figs. l and 3, the bearing` shell for the head end bearing is interior-ly threaded throughout its length, and has both ends open, while the bearing shells for the intermediate bearings have smooth bores, and have their inner ends partly closed by internal annular ribs or fianges 19, while the shell for the tail end bearing is extended, as shown at 20. for a purpose which will hereinafter appear.

eferring more particularly now to the head end bearing, it will be noticed that a box or guide 21 is threaded into the shell lo, and this box or guide is provided on its outer end with an axial annular flange 22, provided upon its outer face with a series of lugs or notches 23, which may be engaged by a Spanner or similar tool for the purpose of turning the said box or guide into the shell or for adjusting the` runner shaft 2t to its proper position in setting up the niill. The bore of this box or guide is smooth for the greater portion of its length and is stepped, as shown at to receive the outer race or ring 26 of an anti-friction bearing` consisting of a pair of concentric rings or races having annular grooves in their opposed eircuiuferential faces and a plurality of balls or rollers 2T seated in the said annular grooves, the exact details of the construction and arrangement being immaterial. The inner end of the box or guide 21 is internally threaded beyond the step 25. as shown at 28, and the cover 29. engaged in the said threaded portion` extends over the inner end of the box or guide and encirclesl the runner shaft 24 clearly shown in Fig. 3. The inner edge of this cover 29 is provided with an annular groove 3() from which a perforation or other passage 3l leads to the interior of the box. The end of the runner shaft is reduced, as shown at 32. and the inner race or ring 33 of the anti-friction bearing fits upon this reduced end of the shaft and against the shoulder 34 thereby formed, a securing nut 35 being threaded upon the extremity of the shaft and turned up against the said race. so as to clamp the saine against the said shoulder, as will be readily understood. As shown in Figs. Il and 9. this clamping nut is split peripherallyl at opposite sides of its center and through the split portion locking screws` :lo are threaded. After the nut has been turned home against the race 33, these locking lill' screws will be turned up so as to clamp the two portions of the nut together, and thereby cause the nut to bind or lock upon the threads of the shaft, so that the nut will not work loose and permit the bearing to move from its position relative yto the end of the shaft. It will be readily noted that the construction and arrangement of the parts described provide abearing which will resist both the radial and the end thrustpf the shaft. so that the shaft will be held in its true horizontal position and axial displacement of the same during the operation of the machine cannot occur.

The cover 29 is held against casual rotation by means of screws or bolts 37 inserted through openings provided therefor near the outer edge of thc cover and threaded into sockets in the end of the guide or box 21, the edge of the cover overlapping the end of the box or guide, as clearly shown in l `ig. 3. dBy providing these fastening screws or bolts 3,7, movement of the cover relative to the box or guide is prevented, so that the release of the bearing cannot occur. An oil or grease cup 38 is carried by the box or guide 21, and is mounted -in the end of the same so as to otl'er no interference withthe assemblingr of the box or guide nor with the adjustment of the same within the bearing shell 16.

The inner bearings are similar in construction to the bearing just described, except that the box or guide 21 is omitted, and the antifriction bearing 39 is mounted within the smooth bore of the shell 16 and fits against the thrust collar 40 provided around the runner shaft 24 and between the anti-friction bearing and the hub 41 of. the head runner. The runner shaft is enlarged diametrically to provide a seat for the thrust collar 40 and the'bearing 39, and is threaded, as shown at 42, to receive a clamping nut 43 similar in all respects to the clamping nut 35, whereby the bearing 39 is held against the end of the thrust collar. The said thrust collar fits closely within the opening through the annular rib or flange,

1S), and over the open end of the shell 1G l secure a cover 44, which is provided in its inner edge. with an annular groove 45. from which an opening or other passage 4G leads intothc interior of the shell. This cover 44 is secured in place by bolts or fastening screws 47 inserted through the cover into the end or edge of the shell, as clearly shown. whereby the cover will be securely held in its position relative to the shell. A grease or oil cup 48 is secured to the top of the shell and leads to the interior of the saine. to supply lubricant to the bearing, as shown and as will be readily understood.

'lhe head runner 49 is provided With a hub 41 which is shrunk upon or otherwise secured to the, inner end of the head runner shaft 24 and to the outer side of the said runner is secured a sealing ring 50 which bears against a sealing ring 5l secured to the adjacent opposed side of the spout 52, as shown in Fig. 1, the lower portion of the spout encircling the hub of the runner and being secured rigidly to the shell or casing 53. as will be readily understood. The said shell 53 has anopening'in one sideto accommodate the end of the spout and the sealing ring 51 secured thereto, and is preferably constructed inv sections 54 secured together by locking levers or other devices 55, whereby the casing or shell may be readily assembled around the runners, as will be readily understood upon reference to Fig. 2. The head runner 49 is, of course, equipped with a grinding plate 56, which may be of any well known or preferred design.

The inner bearing for the tail` runner shaft 57 is a duplicate of the inner bearing for the head runner shaft, except that the cover is at the opposite side of the center of the mill. T he said shaft 57 extends into the casing or shell 53 and the tail end runner 58 has its hub 59 shrunk upon or otherwise rigidly secured to the end of the shaft, as will be readily understood. A. rinding plate (S0 is secured upon the face of the tail end runner 58 and coacts with the grinding plate 56 upon the head runner to grind the grain or other material passing through the- Secured to the mill in the usual manner. outer side of the shell immediately adjacent and extending to the hub 59 is a packing box or .bearing 61, consisting of two. circular plates or rings secured together and to theshell and having their inner edges oppovStill sitely beveled, so as to clamp a felt or other washer 62 which will bear upon the hub and thereby prevent the passage of dust throughl the shell around the hub, and, consequently, counteract the tendency of dirt to accumulate around the hub and'create excessive friction which has been encountered in mills previously constructed. It will be readily observed that the construction of this box permits the felt or other washer to be readily renewed when worn or to be adjusted so as to take up the wear as long as there is suiiicient fabric left to be held byithe circular plates or rings. Band pulleys (S3 are secured upon `both runner shafts intermediate the ends thereof, so that motion may be imparted to the said shafts to operate the mill, as will be readily appreciated.

The shell or housing 16 for the tail end bearing, as before stated, is provided with a cylindrical extension 20 having a central opening throu h which a step box 64 projects and the ore of this extension is angular, preferably hexagonal, to receive the angular head b5 of the said step box, whereby the step box may be permitted to move longitudinally of the shell, but will be held c meshes of the extension or shell 2O is smooth throughout, but the end of the step box is threaded to be secured in the end of a relief box 69, as shown. Between the outer end of the shelland the head 65 of the step` box is coiled an end-thrust spring which normally holds the step box inwardly away from the end of the shell and the relief box vagainst the end of the shell. n'exeessive lncrease of pressure upon the spring, however, as by the entrance ot' an excessively large and hard substance between 'the grinding plates, will cause the relief box to move away from the shell to accommodate the axial movement of the runner shaft. he tensionot this spring may be adjusted by .rotating the relief box whereupon the threaded connection ot the same with the step box, will efl'ect a longitudinal moienient of the` latter and compress the spring, a vsingle revolution ot' the rel-iet' box being suflicient to etlect a perceptible increase in the tension of the spring. .fitter adjustment, the relief box is h ld against rotation relative to the shell b v a pin or key 'il inserted through alined openings in lugs 72 on the shell and the box. as clearly shown, and as will be readily understood.

The center guide plug 38 has its inner end expanded. as shown at il. to torni a head or piston fitting within the expanded bore or chamber Tl ot' the shell. and the said head or piston is provided at its top with a groove or opening T5 which will permit the air within the chamber to from one side of the piston or head to the opposite side thereof to equalize the pressure on the two tacos of the piston. and thereby` avoid choking or impeding the movement in the operation of the device. A grease or oil cup Til is mounted on the upper side of the shell iinmediately over this opening T5, and the lubricant from the said cup will pass on to the piston and find its way through said opening to the bearing Ti' within Ahe shell. as will be readily understood. the pin 6i' serving as a stop to prevent the escape of Vthe lubricant to and throuffh the outer end ot' the shell. rl`he said bearing i? is preferably oi the type previously described. and is held upon the end oi? the tail runner shaft 57 by means of a clamp nut T8 hal-cling the inner race against an annular shoulder on the shaft. as clearlj.' shown ifi# 'r' outer race of this bearing has diameter which will permit it to within the smooth bore or chamber shell and this race is held by and between the annular edge of the head or pistou Tl and a safety spring guide sleeve S0 mounted within the said chamber and encircling the end of the runner shaft. This sleeve d() is formed with an annular recess or' socket Sl which receives one end of a safety spring S2 coiled around the shaft and having its op posite end bearing against the cover plate Sil secured to and extending across the inner end of the shell. as clearly shown in Figs. l and 8. This cover is provided with an annular groove Si in its inner edge and an opening S5 leading therefrom into the ebano ber 74. and is also provided with a central annular rib or collar 86 which lits closely around the runner shaft and serves as a su pport for the end of the safety spring.

rlie outer end of the relief box 35) is closed by a removable cap i?? through which is threaded a tail screw SS equipped with a hand wheel S9 and a jam nut Q0. rl`he inner end ot this screw S8 bears against the outer side of a` cam box Dl which is mounted concentrically within the relief box lifl and is spaced therefrom to reduce friction b v lon gitudinal projections or spacing ribs fr. on its outer surt'acc. ln the sides oi this box. at diametrically opposite points of the same. l Jform open-ended notches or slots 92' which register with slots 93 in thc sides of thc ro- -liet box. and upon the inner tace ol'l the back wall of the cani box l provide a rib or bearing strip 94. Between this bearing strip or rib 94 and the outer end ol the center guide plug (3S, l arrange a releasing,r cam 95. which is mounted upon a cam shalt lf. the ends of which project through the slots 93 in the relief box and are mounted to rotate within the same. Longitudinal movcnient ot the cani shaft is prevented b v nicans of an annular shoulder or cnlargclncnt 51T on one end of the same and a retainingr disk or stop 9S secured to thc opposite cnil thorooi". said collar and stop bearing against tbc opposite outer sides ot' thc rclictl box. as shown most clearly in Fig. 1l. .Xn operating lever 99 is secured to one end ol tbc cani shaft. so that the operator may readilyY throw the said shaft to the released or the holding position. when such action is neccssauv. The cam is substantially an elliptical block so arranged as to provide opposite parallel t'aces furnishing straight bearings against the rib 95k and the end ot the center guido plug. as clcarij.r shown in Fig. l2. two of said faces being at a greater distance apart han the intervening two faces. and said more distant faces being curved concentric with the cani shaft. as clearly shown. the said curved faces being indicated at lll() and inl. while the intervening' tacos arc indicated at i102 and llll. line cud of thc cani is `formed with a cylindrical trunnion lill, while at lthe opposite end is a cam trunnion O5 havingr outwardly proiecting diametrilil.

lli

- cam trunnion lll lib

lconsequently,

Avtion.` llt w1 cally opposite stop shoulders or corners 105', o the extremities of which are vat a greater distance from the center of the cam shaft than are the sides 'of the trunnion. The purpose of this peculiar construction of the is clearly shown in Figs. 13 and.A it. When the cam 95 is larranged as shown in Figs. 1, 8 and 13, to spread apart the cam -box 91 and the center guide plug'GS, the carntrunnion 105, will'occupy t e position shown in vlig. 13, in which the greatest radius of the cam trunniin will incline upwardly toward the'outer end of the mill, 1n which position, `if itbe. attempted to move the lever downward toward 'the end rof the mill, the corners 105 of the cam trunnion will bebrought against the upper and lower walls of the. notch 92 in the cam box, and,

rotation of the vcam in that direction will be prevented. Movement of the cam in the opposite direction, howevenwill be permitted, owing to the fact that the Vedges or. sides of 'the cam trunnion between .the extended points 1054 are 'curved on a radius which terminates short of the walls of the notch and', consequently,.the cam shaft may be'turned to the position shown in Fig. 1li, in which ythe greatest radius of the cam trunnion will incline downwardly toward the rear end of the mill. .-'llhe movement of the cam beyond the position shownin lFig. 1t will be-prevented by the extended cor ners of the cam trunnion, coming into contact with the walls of the notch 92 opposite the walls previously engaged by the said corners, respectively, an 1t will therefore be Vseen that the cam shaft can rotate only through one quarter of a circle, and, conseuently., it is impossible for the operator to t row the lever' through an are greater than that necessary for the proper operation of the releasin device or in the wrong-direcl be readily appreciated that if the cam could' be swung through one-halfa revolution, the relative positions of the relief and step boxes would bethe same asY that occupied previous to the movement, so that the releasing devices would prove ined'ective, and' considerable difficulty and trouble has been occasioned heretofore by the operator imparting excessive movement to the releasing cam. By my present construction this excessive movement is positively prevented. 4 llt will be readily observed from the foregoing description, taken inl connection with the accompanying drawings, that when my mill has been set up in itsoperative position, the runner shafts lwill be supported positively and xedly in'axial alinement, so thatv the runners will be maintained with their working 'faces in parallel relation through the life of the machine. llt will be observed that my mill dispenses with the elongated hearings heretofore considered necessary and substitutes therefor short bearing supports in which the frictional engagement is reduced to a minimum sothat the radial and 4end thrust of the runner shafts will be effectively taken up without creating a large amount of friction. As the number. of parts is so greatly reduced and the moving points of support are so few, the frictional resistance is practically eliminated, and, consequently, wear upon the shafts or their supports 1s overcome, so that the axial alinement of the shafts is preserved, and no necessity for tramming the mill will arise. ln my present mill, the only adjustment required after the mill has been set up is the longitudinal adjustment of the runner shafts to compensate for wear upon the grinding plates and upon the sealing rings. To accomplish this adjustment of the head runner shaft, the box or guide 21 is rotated so that it will ride longitudinally in the end shell 16 .by vreason of its threaded connection therewith, and this longitudinal movement of the said box or guide will be' transmitted to the runner shaft through the bearing 26, inasmuch as the said bearing is clamped to the box or guide by the cover 29 and also clamped to the runner shaft by the nut 35. As the anti-friction bearing 39 of the inner support or bearing is mounted lwithin a smooth-bored shell, the said bearing will readily follow the movement of the shaft within the said shell, so that the engagement 4and relative positions of the runner hub, the thrust collar, and the clamping nut relative 'to the said bearing will not be disturbed. A

similar adjustment of the tail runner shaft may be edected by rotatin the tail screw 88, this action causing sai screw to move the/cam box 91 longitudinally of the relief box, and this movement will be transmitted directly to the runner shaft through the center guide plug and the bearing 77. As the safety .s ring acts through its guide sleeve to hol the bearing against the head of the center guide plug', the several parts will follow the movement of the tail screw in either direction. When' the desired adjustment has been edected, the jam nut 90 is turned home to hold'the parts in their adjusted relation. Should the material pass into the space between the grinding plates in an excessive quantity, the resistance of such 'witha to a vertical position, which will cause the releasing cam to assume the position shown in Fig. 14, whereupon the safety spring will at once expand and move the runner shaft outwardly by the pressure exerted upon the shaft through the guide sleeve 80, the bearing 7T and the center guide plu 73. The runners will thus be separated su ciently to permit the foreign substance to pass from the mill, the cam beingsubsequently returned to its normal position, indicatedl in Figs. 1, 8 and 13, and thereby moving the several parts in opposition to the safety spring to return the runner shaft with its attached runner to its working position. It will thus beseen that I have provided means whereby the end thrust upon the runner shaft will be taken up while axial movement of the said shaft is permitted, so that the runners Will be held to their work but injury to the grinding plates by means whereby the moving of the grinding faces back to their working positions, ,before the foreign matter has been discharged, is prevented.

' rI-he moving parts of my mill are preferably lubricated by thick lubricant fed into the bearing chambers `or supports from grease cups lmounted on the said supports. This lubricant has a well known tendency to work around a moving shaft or other element, and by reason of this tendency will travel along the shaft toward the cover plates. When it reaches the grooves in the inner edges of these plates, centrifugal aotion occurs, so that the lubricant is caught in and travels around the said grooves and then escapes therefrom through the openings at the lower portions of the same, and is consequently returned to the chambers within which the shaft rotates. Loss of lubricant and collection of the same upon the outer surfaces of the mill is thereby prevented and, consequently, the collection of grit upon the shaft and the bearingssis avoided, so that wear upon the shafts and forcing of the same from their axial positions is obviated. It is clear from the drawings that the bearings are completely housed and protected against the entrance of flying particles of dust -so that smooth easy running of the mill is assured.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In an attrition mill, thecombination of supporting edestals having bearing seats :formed in tlieir upper ends, bearing shells rigidly secured in said seats,A bearings mounted slidably within the shells, and a shaft extending through the shells and mounted in said bearings.

2. In an attrition mill, the combination plurality of alined supports, of a foreign substances will be prevented, and'have also provided` 'ting against the said bearing,

bearing carried by the upper end of each support and adapted to resist thrusts from two directions, and a runner shaft extendmg through and supported by said bearings.

f. 4. The combination, in an attrition mill,

of a casing, a runner having its hub extending through theside of the casing, a pair of circular plates secured to the outer side of the casing, and a washer secured between said plates and extending to and fitting around the end of the hub.

5. In an attrition mill, thecombination of a bearing shell having an axial extension at its outer end, a step box slidably mounted in said extension, an end thrust spring coiled around the step box and bearing against the head of the same andthe end of the extension, a relief box secured upon the outer end of the said step box, a guiding plug extending through the said step box and having an enlarged inner end, a runner shaft having its end entering the said shell, a bearing secured on the end of the said shaft and fitting against the enlarged end of the guide plug, a guide sleeve on the shaft lita spring bearing upon the said sleeve and the end of the shell, and means within the relief box whereby the guide plug may be held to the end of the shaft or may be permitted to move quickly outward in the shell.

6. In an attrition milk-the combination of a runner shaft, a shell surrounding the end of the shaft, a spring in the shell beyond the end of the shaft tending to hold the shaft in an inner position, a lesser spring within the'shell around the end of the shaft tending to move the shaft outward, and means forI releasing the greater spring to permit the lesser spring to act. Y

7. In an attrition mill, the combination of a runner shaft capable of longitudinal movement, a casing inclosing the end of the shaft, means for holding the shaft normally inward, means tending to move the shaft outward, and controlling devices -whereby the shaft may be released from its inner position and -moved outward, saidmcans which tend to move the shaft outward being housed within the casing.

8. In an attrition mill, the combination of a runner shaft capable of longitudinal movement, a bearing secured around said shaft, an end thrust spring, a safety spring, and intermediate devices whereby said springs act upon the bearing in opposition to each other.

9. In an attrition mill, the combination with a runner shaft, and an end thrust bearing therefor, of a relief box, a cam box mounted in the relief box and having lon- ISU maaoaa gitudinal slots in its sides, a cam bearing upon said box and a member of the end thrust bearing to connect or release the same, and trunnions at they ends of said cam playing in the slots in the cam box, one of said trunnions having unequal radii and its longest radius being greater than the width of the slot in which it plays.

l0. lin an attrition mill, the combination witha relief box, and a guide plug having its end within the same, of a cam box having a slot in its side and mounted within the reliefbox, 'a cam within the said cam bearing against the same and the end of the guide plug, a cam trunnion at one end of the cam playing in the slot in the side of the cam box and adapted to impinge against the walls o f said slot whereby the movement of the said trunnion and the cam will be limited.

l1. An attrition mill having in combination a plurality of slidably mounted bearings spaced apart and each arranged to resist both radial and end thrust, a runnershaft mounted in said bearings, and means for adjusting said bearings, whereby said shaft may be adjusted longitudinally.

1Q. ln a grinding mill, the combination with a base frame, standards thereon, longitudinally movable bearings mounted on adjacent standards, a shaft journaled in said bearings, an axially alined shaft mounted on the other standards, and grinding disks on the inner adjacent ends of said shafts; with means for moving said movable bearings longitudinally on the standards to move the shaft bodily and separate the disks without disturbing the grinding adjustment of said shaft in its bearings.

13. lin a grinding mill, the combination with a base frame, standards thereon, longitudinally disposed shafts mounted on said standards, and grinding disks on the inner adjacent ends of said shafts, bearings for said shafts mounted on the standards, each shaft being su ported on two standards, both bearings or one of said shafts being slidable longitudinally on their standards; with means adapted to engage one of said slidable bearings to move it and thereby the shaftand its other bearing and its disk longitudinally of the frame without disturbing the grinding adjustment of said shaft in its bearings. l

14. ln a grinding mill the combination of a base, axially alined standards thereon, a housing. bearings on said standards, a pair of axially alined shafts mounted in the said bearings atiopposite sides of thehousing and extending into the housing, grinding disks on the ends of said shafts within the housing. the bearings for one of said shafts being slidablv mounted on their standards and the shaft supported by said movable bearings beingrotatably but normally longitudinally iminovably journaled therein; with means for simultaneously shifting both said bearings longitudinally of the base and thereby moving the shaft longitudinally without disturbing the grinding adjustment of said shaft in its bearings.

l5. lln a grinding mill, the combination of a housing formed with an extension or neck, grinding heads, a rotary shaft carrying one of the heads and extending into the housing, said shaft being movable longitudinally in opposite directions to carryits grinding head to and from the opposing head, a spring arranged within the housing and acting to urge the shaft in a direction to separate the heads, and a second spring of stronger tension arranged in the neck of the housing and acting to urge the shaft in a contrary direction.

16. ln' a grinding mill, the combination of a fixed frame or housing, grinding heads, a shaft carrying one of said heads and movable longitudinally in a direction to carry its head away from the opposing head, releasable means for holding the heads in grinding relation to each other, lan antifriction bearing betweenA the shaft and frame, said anti-friction bearing comprising an inner member fixed to the shaft, an outer non-rotatable member movable longitudinally in the housing, and a series of inter-l posed rolling elements serving to hold said bearing members against relative movement longitudinally, and a spring acting to urge the outer bearing member longitudinally 1n thedirection of the longitudinal movement of the shaft to separate the heads when said means are released.

17. lln a grinding mill, the combination of a frame or housing, grind-ing heads, a rotary shaft carrying one of `the heads and movable longitudinally in a direction to separate its head from the opposing head, releasable means for holding the heads in grinding relation to each other, a non-rotatable member mounted to slide longitudinally in the housing with the shaft, a non-rotatable sleeve mounted in the housing and engaged by and movable longitudinally with said member, and a spring engaging between the` housing and said sleeve and tending to shift the shaft in a direction to separate the heads when said means are released.

i8. ln a grinding mill, the combination of a frame or housing, grinding heads, a rotary shaft carrying one of the heads and movable longitudinally to carry its head away from the opposing head, a non-rotatable -member mounted in the housing to move longitudinally with the shaft, a spring between the housing and said member tending to separate the heads, a second non-rotatable member mounted to slide longitudinally in the housing and engaged by the first mentioned member, and a spring acting to urge said seclll@ -lllti shaft Carrying one ofthe heads and mounted in the housing to move longitudinally to cai-ry its head away from the opposing head,

a non-rotatable member mounted to move longitudinally inthe housing with the shaft,

a second longitudinally movable member engaged by the first member and provided with an axial extension, and means for yi'eldingly supporting the end thrust of said axial extension.

20. ln a grinding mill, the combination of a frame or housing, grinding heads, a rotary shaft carrying one of the heads and mounted in the housing to move longitudinally to carry its head away from the other head, a non-rotatable annular member mounted in the housing exterior of the shaft and movable longitudinally with the shaft, a second non-rotatable member engaged by the first mentioned member and mounted to' move longitudinally and means for yieldingly supporting the end thrust of said second member.

21. In a grinding mill, the combination of 'able longitudinally with the shaft, an

shaft carrying one of the heads and movable longitudinally to carry its head away from the opposing head, a non-rotatable member exterior to the shaft in which the shaft is rotatably mounted, said member bein movt? yielding means eoperating with said member and tending to `urge the same and shaft in a dire'ction to move the grinding heads together. 22. ln a grinding mill, the combination with a base frame, longitudinally disposed shafts mounted thereon and opposed grinding disks on the inner adjacent ends of said shafts, a set of independently adjustable bearings for one of said shafts; said adjustable bearings being simultaneously slidable with the shaft longitudinally of the base to permit said shaft and its disk to be moved longitudinally of'the frame to bodily sepa-y rate the disks.

In testimony whereof l affix my signature, in presence of two witnesses.

JOHN S. SORENSEN.

Witnesses:l

STEPHEN Soana, J. RUSSELL SMITH.

Ya. frame or housing, grinding heads, a rotary asA 

